TCP_KEEPALIVE not supported

Index: src/net/serveraccepthelper.h
--- src/net/serveraccepthelper.h.orig
+++ src/net/serveraccepthelper.h
@@ -245,6 +245,7 @@ class ServerAcceptHelper : public ServerAcceptInterfac
                     int keepidle  = 30;   // seconds until first keepalive probe
                     int keepintvl = 10;   // seconds between subsequent probes
                     int keepcnt   = 6;    // number of failed probes before disconnect
+#if !defined(__OpenBSD__)
 #if defined(__APPLE__)
                     setsockopt(fd, IPPROTO_TCP, TCP_KEEPALIVE, &keepidle,  sizeof(keepidle));
 #else
@@ -252,6 +253,7 @@ class ServerAcceptHelper : public ServerAcceptInterfac
 #endif
                     setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &keepintvl, sizeof(keepintvl));
                     setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT,   &keepcnt,   sizeof(keepcnt));
+#endif
                     // TCP_USER_TIMEOUT: abort connection if data remains
                     // unacknowledged for 90s (matches keepalive detection).
                     // Without this, a dead client can keep the server
